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Lowering springs for oem boss shocks

eng90

TMO Race
232
2
good day,

i am planing to lower my car and at the same time i would like the best springs for track racing my boss 302.

My boss has full front stock suspension ( other than blowfish brake cooling ducts) and rear stock suspension with bmr ucas, lcas and relocation brackets.

I think i would need panhard bar to re align the diff after lowering the car... do i also need more parts to change too ?

There are many spring heights and rates and if other mods are required other than the panhard bard please advise.
 

Norm Peterson

Corner Barstool Sitter
When you say 'track', do you mean mostly road courses or mostly drag strips and other forms of straight line running?

My personal thoughts as far as choosing springs goes is to choose based on spring rates for your use and generally shoot for less lowering rather than more. Function > appearance if you're not being judged at a car show.


Norm
 

eng90

TMO Race
232
2
When you say 'track', do you mean mostly road courses or mostly drag strips and other forms of straight line running?

My personal thoughts as far as choosing springs goes is to choose based on spring rates for your use and generally shoot for less lowering rather than more. Function > appearance if you're not being judged at a car show.


Norm
Thank you for your input.

I drive my car in circuit track. And yeah with regards to lowering i dont prefer slamming the car to the ground and i am all about function for racing im not into looks and car shows.
 

AdmirC

TMO Intermediate
81
37
Vancouver BC
Many people have had success with the Ford Racing P springs. They do make a boss specific T spring which should work well also. If you want more of a hardcore spring then the H&R race springs or Maximum Motorsport springs would be a good bet. I would recommend an adjustable panhard bar not only to center the axle but it makes the car more predictable not having the deflection of the original bushing.
 

Beermoney

TMO Intermediate
I have the T springs on my 13 boss with stock suspension, everything seems to work well together. It does take nearly all of the rake out of the car though if that's a concern for you.
 

blacksheep-1

Epic Contributor
2,664
2,220
The Boss 302, especially the Boss302 LS version is a serious road car, if you don't find what you are looking for, I'd research those parts and go that route.
 

Dave_W

Cones - not just for ice cream
107
97
Connecticut
Autocross
20+ Years
Steeda also has a Boss-specific set of lowering springs. They also sell the Ford Racing "P" spring set for Bosses.
 

eng90

TMO Race
232
2
Thabk you guys but these are so many options to choose .... is their spraing rates close to each other ? Is there one better than other for track racing ??

I think the lower the car the better it is at the track or is that not true ?? Because in case if it isnt i think ill go for the p springs from ford performance.
 

AdmirC

TMO Intermediate
81
37
Vancouver BC
If your looking for pure track performance and want to stick to OEM style springs and not coilovers. H&R race springs or MM springs are your best bet, I think they have the highest rate of any stock type spring and I think they are the same spring so whichever you can get cheaper. Mind you they don't ride very nice on the road but they are tolerable.
 

Dave_W

Cones - not just for ice cream
107
97
Connecticut
Autocross
20+ Years
I think the lower the car the better it is at the track or is that not true ??
Only if the suspension geometry is changed to compensate. In theory, when designing a car the lower the Center of Gravity the better, but in practice on a car that's already built, lowering the car changes the angles of the suspension arms and steering tie rods from their designed range. Lowering "too much" can change the angles to the point that handling becomes worse than stock due to increases in roll center migration and bump steer. That's why both the Ford "P" and Steeda springs only lower the front end a small amount. (I don't know about the other springs mentioned.) They lower the rear a bit more as the rear axle roll center geometry is less sensitive to lowering because of the panhard bar design. For changes in anti-squat from lowering, the easy fix is a set of rear lower control arm relocation brackets. An adjustable panhard bar can re-center the axle if you lower a good amount in the rear and want to get fancy. Lowering the rear a lot can change differential pinion angle, necessitating adjustable rear lower and/or upper control arms. As you can see, the more you lower the car, the more other things need to be changed to compensate.
 

Norm Peterson

Corner Barstool Sitter
I think the lower the car the better it is at the track or is that not true ?? Because in case if it isnt i think ill go for the p springs from ford performance.
In addition to what Dave_W just posted, lowering a strut-suspended car generally does not gain as much cornering performance as the visual amount of lowering may suggest. While it's true that the total amount of lateral load transfer is reduced, more of that load transfer is being taken through the suspension and the amount of roll would increase if you held the spring stiffnesses the same as before. That's because the geometric roll center drops quite a bit more than the amount you lower the car (double being a reasonable estimate without making all the necessary measurements). In normal situations, at least some of the extra stiffness you paid to get along with the lowering is more or less "wasted" just keeping the car from rolling any more than it did when it was 100% stock. Wheel camber, and tire grip being a vague function of camber are the downstream effects.

Yes, lowering the CG height reduces the total load transfer, so the outboard tires effectively do "gain" in terms of friction coefficient. However, the inboard tires stay loaded a bit more than before, so their effective "mu" value drops a little. Overall, the net gain is less than the gain looking at the outboard tires alone. Lowering a car with a 20" CG height by 2" (10%) might buy you a 3% skidpad improvement in the 1.0 - 1.1g cornering neighborhood. Of course you'd chase 3% effects if you were actually competing (and driving consistently enough to be able to reliably take advantage of it). For a dual-purpose street/HPDE track car, perhaps not. Particularly not if, as Dave has mentioned, you don't include corrections for things like anti-squat/axle roll steer and bumpsteer in your build that your lowering would have affected.

I think people tend to overlook what a stock/stockish ride height Mustang is capable of, and see "more" only as being "more than not very good".


Stock height (and soft stock springs). Aim Solo datalogging. Mild suspension mods (sta-bars, shocks/struts, and alignment, nothing crazy or secretive going on here) and a better wheel (18x11) & tire (MPSS) package than stock, but the OE ride height and spring stiffnesses aren't limiting it all that badly.
1.30g.jpg


15-2-4 T'bolt T12.jpg



Norm
 

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